In semiconductor manufacturing, multiple layers (such as a SiN layer, a high-K layer, a poly layer, etc.) are deposited on the front side of a wafer, in which an adhesion layer (such as SiN) plays an important role for adhering the other layers to the wafer. During deposition of the layers, the layers are unintentionally deposited on the backside of the wafer with little or no adhesion layer. After the deposition of the layers, the wafer still needs to undergo several subsequent processes, in which some processes may cause a high stress difference between two adjacent layers, and some processes with high thermal budgets may induce large thermal stress in the layers. Such high stress difference and thermal stress may result in backside peeling defects on the wafer, especially on the region of the backside of the wafer on which little or no adhesion layer is formed. The more the layers are deposited on the backside of the wafer, the higher the peeling defect failure rate will be. Therefore, the backside peeling defects of the wafer can be avoided by preventing the layers from being deposited on the backside of the wafer.